1. Field of the Invention
This invention relates in general to a vibration insulating device of the type wherein an elastic support member is interposed between inner and outer cylinders, and more particularly to improvements in such an vibration insulating device to prevent damage of the elastic support member due to tensile force applied thereto.
2. Description of the Prior Art
Vibration insulating devices of the type wherein an elastic (elastomeric) support member is interposed between inner and outer cylinders have been used as engine mounts, cab mounts, bushings or the likes. Such a vibration insulating device is disclosed, for example, in Japanese Patent Provisional Publication No. 61-65935, in which the elastic support member is formed with two liquid chambers which are located on the opposite sides of the inner cylinder. The two liquid chambers communicate with each other through a restriction passage. With this arrangement, vibration applied between the inner and outer cylinders causes expansion and contraction of each fluid chamber, so that liquid moves between the two liquid chambers through the restriction passage. In this process, vibration is damped by flow resistance of fluid which flows from one liquid chamber through the restriction passage to the other liquid chamber.
However, difficulties have encountered in such a vibration insulating device upon being set in a usuable position in which a load of a supported body is applied to the elastic support member. When the load of the support body is applied to the elastic support member, a larger tensile force acts on the side walls defining the liquid chamber located upward of the inner cylinder. This larger tensile force will cause the elastic support member to be cracked, thereby deteriorating durability of the vibration insulating device.